High-speed door operator

ABSTRACT

A DOOR OPERATOR ADAPTED TO MOVE AN UPWARDLY ACTING DOOR ALONG TRACKS BETWEEN OPEN AND CLOSED POSITIONS. THE OPERATOR INCLUDES A CARRIAGE MOUNTED UPON A SUBSTANTIALLY HORIZONTAL RAIL EXTENDING PERPENDICULARLY AWAY FROM THE CLOSED POSITION OF THE DOOR. AN ENDLESS CHAIN IS ARRANGED IN AN ELONGATED LOOP EXTENDING ALONG THE RAIL AND SUPPORTED FOR MOVEMENT RELATIVE THERETO. ONE END OF THE LOOP CAN ROTATE A SHAFT MOUNTED ABOVE THE CLOSED POSITION OF THE DOOR. CABLES ARE CONNECTED BETWEEN THE SHAFT AND THE LOWER EDGE OF THE DOOR. DRIVE MEANS ON THE CARRIAGE ENGAGES THE CHAIN AND CAUSES THE CARRIAGE TO MOVE RELATIVE TO THE CHAIN AND THE RAIL. LINKAGE CONNECTS THE CARRIAGE TO THE DOOR AND COOPERATES WITH THE CABLES FOR OPENING AND CLOSING THE DOOR.

D. S. HARRIS HIGH-SPEED DOOR OPERATOR Nov. 2, 1971 3 Sheets-Shea(l l Filed OCT.. l, 1969 NN m.. Q hq N/ u Q E.

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D. S. HARRIS HIGH-SPEED DOOR OPERATOR Nov. 2 1971 3 Sheets-Sheet 2 Filed Oct. l 1969 WR. mg ,iwf mw M M 0 D. S. HARRIS HIGH-SPEED DOOR OPERATOR n Nov. 2;'1911 3 Sheets-Sheet 3 Filed 001'.. l, 1969 Q INVENTOR.

/VLD 5 #AP6/5' BY //Jw M @gw United States Patent Oce 3,616,575 HIGH-SPEED DOOR OPERATOR Donald S. Harris, Dallas, Tex., assignor to Overhead Door Corporation, Dallas, Tex. Filed Oct. 1, 1969, Ser. No. 862,688 Int. Cl. EtlSf /12 U.S. Cl. 49-200 11 Claims ABSTRACT OF THE DISCLOSURE A door operator adapted to move an upwardly acting door along tracks between open and closed positions. The operator includes a carriage mounted upon a substantially horizontal rail extending perpendicularly away from the closed position of the door. An endless chain is arranged in an elongated loop extending along the rail and supported for movement relative thereto. One end of the loop can rotate a shaft mounted above the closed position of the door. Cables are connected between the shaft and the lower edge of the door. Drive means on the carriage engages the chain .and causes the carriage to move relative to the chain and the rail. Linkage connects the carriage to the door and cooperates with the cables for opening and closing the door.

FIELD OF THE INVENTION This invention relates to a door operator for an upwardly acting door and, more particularly, to a type thereof which, while it moves the door between the open and closed positions, automatically compensates for variations in the speed of movement of different parts of the door to which the operator is connected.

BACKGROUND OF THE INVENTION Door operators for moving an upwardly acting door or other closure member between open and closed positions are old in the art. Generally speaking, they comprise some type of mechanism which engages the upper portion of the door and moves along rail means. However, it is well known that, as the door departs its fully closed position or approaches its fully open position, rthe rate of movement of one of the upper and lower edges of the door is relatively small by comparison to the move- -ment of the other edge.

That is, for example, as the door initially moves upwardly and rearwardly away from its closed position, the upper edge of the door moves horizontally away from the wall at a much faster rate than the lower edge of the door moves upwardly away from the threshold. Thus, where the door operator includes cable means connected to the lower edge of the door (which is desirable if not essential with large one-piece doors), it becomes diicult, if not impossible, to compensate for the difference in the speeds of the two parts of the door without using separate drives for the cables and carriage. Moreover, this difference is the speed of movement of each part of the door varies as the door moves toward or away from its closed position. Where no cables are used, the force required from the carriage to effect the iinal movement of the lower edge of the door into its raised position greatly exceeds the force required from said carriage to move the lower edge of the door in the lower half of its upward movement. However, if cables are used to assist in such upward movement, some means must be provided for a differential in the speeds of cable and carriage movement.

In studying this problem, it became apparent that the double drive mechanism could be avoided by providing differential means to compensate for the diifering door movements as the door is moved between the closed and 3,616,575 Patented Nov. 2 1971 open positions. However, until the invention of this application was developed, differences and/or variations in the aforsaid movements of different parts of the door could not be effected, by using a single, constant speed drive without providing so complicated a piece of equipment as to preclude its use, particularly for commercial installations. The big problem was to coordinate, automatically, the differences and variations in the movements of the various parts of the door while using one drive mechanism. It was also essential that the desired device should be capable of adaptation to conventional spring-biased counterbalance mechanisms, which include the door-engaging cable means.

A particularly critical point in the operation of a onepiece upwardly acting door, the lower end of which is not positively raised by cables or the like, occurs just as the door approaches the fully open position when the horizontal movement of the upper edge of the door is very small by comparison with the vertical movement of the lower edge of the door. It is also at this point that the tension normally provided by a counterbalance spring is the least and, at the same time, the Vertical vector of force applied to the lower edge of the door by the operator attached to the upper end of the door is the least. Thus, it is not uncommon to observe a steady increase in the amount of droop of the lower edge of a one-piece door when it is supposed to be in its fully open position, even where lcounterbalance means is provided. Moreover, the operator may be damaged by attempting to move the door into the fully open position against such forces.

It becomes particularly important to provide a counterbalance mechanism for a heavy, upwardly acting door which is used to cover the entrance to a walk-in cooler or which is used as a fire door, for example. In case of an emergency, it is entirely possible that the driving mechanism of the door operator, such as an electric motor, may become inoperatable due either to its own failure or to a failure in supply of electrical energy. Without some type of counterbalancing mechanism, it could be virtually impossible to open some upwardly acting doors by manual operation. Nevertheless, unless the forces applied by the operator to the upper and lower edges of the door can in some way be adjusted to the speeds and positions of the parts of the door, the door operator which is connected to the upper end of the door is required to carry unusually large loads at certain points in the operation of the door as, for example, just i as it approaches the fully open position. It is well known that, as the door operator is made more powerful, it must also be sturdier, hence heavier, which means that the rail structure supporting the operator and its connections to the door must be stronger and heavier. This extra weight and strength add to the cost of the installation both in materials and labor.

It follows from the foregoing that, -by balancing the loads imposed upon the cables and carriage of the door operator, particularly as the door approaches its open position, the power and the weight of the operator can both be reduced.

Accordingly, a primary object of this invention is the provision of a door-operating mechanism capable of use with a counterbalance and adapted to balance automatically the forces applied by the operator to the various parts of the door as the location of the load of the door changes, whereby excessive loads on the door operator during the movement of the door are avoided.

A further object of this invention is the provision of a door operating mechanism including a carriage mounted upon rail means'and connected to the upper end of the door, door lifting cable means supported from above the 3 closed position of the door and connected to the lower edge thereof, and a single differential drive means for moving the cable means and carriage means at different rates of linear speed.

A further object of this invention is the provision of a door operator mechanism, as aforesaid, which is relatively simple in construction and operation, which requires a minimum of operating space, which can be connected to conventional, existing upwardly acting doors, particularly of the one-piece type, and which can bc adapted for use with conventional spring-biased counterbalance mechanisms.

Other objects and purposes of this invention will become apparent to persons familiar with this type of equipment upon reading the following descriptive material and examining the accompanying drawings, in which:

FIG. 1 is a broken, perspective view of an upwardly acting door assembly including the door operator of the invention.

FIG. 2 is a sectional view taken along the line II-II in FIG. l.

FIG. 3 is a sectional view taken along the line III- III in FIG. 2.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 1.

FIG. 5 is a sectional view taken along the line V-V in FIG. 4.

SUMMARY OF THE INVENTION The objects and purposes of the invention, including those set forth above, have been met by providing a door operator for an upwardly acting door assembly including a rail which extends perpendicularly away from the wall in which the door opening is provided and directly above such opening. A carriage is mounted upon the rail for movement lengthwise thereof and is connected to the upper end of the door, which is preferably one piece, but may be comprised of a plurality of horizontally hinged sections. An endless, elongated element, such as a chain r having extensive horizontal reaches, is movably supported at the rear end of the rail and also upon a shaft near the front end of the rail. The shaft, which may be part of a spring-biased counterbalance, supports a pair of drums having cables mounted thereon and secured to the lower end of the door for opposing forces of gravity in a substantially conventional manner. The carriage includes sprockets engaged with the chain and drive means for rotating at least one of the sprockets. When the drive means is energized, it moves the carriage along the rail by virtue of engagement between the driven sprocket and the chain. Moreover, the chain is also moved relative to the rails whereby the shaft is rotated to wind or unwind the cables on the drums. The speed of movement of the chain relative to the rails and the carriage depends upon the position of the lower edge of the door, and the carriage drive is a constant speed motor mounted on the carriage.

DETAILED DESCRIPTION The door assembly appearing in FIG. l includes a door 10 which is designed to cover an opening Ill in the wall 12 which can be either an outside wall or a partition wall. The door, which is a one-piece door in this embodiment', has a pair of lower rollers I3 and 14 which are mounted upon the opposite lower ends of the door and disposed within the vertical tracks In and I7, respectively. A pair of upper rollers I8 and I9 are mounted upon the opposite upper ends of the door 10 and are disposed within the horizontal tracks 2.2 and 23. The lower ends of the vertical tracks In and 17 are curved frontwardly toward the Wall .i2 and the front ends of the horizontal tracks 22 and 23 are curved downwardly in order to improve the sealing engagement of the door I() with the interior surface of the wall l2. The door l0. the tracks I6, I7, 22 and 23 and associated parts may be substantially as disclosed in detail in the copending application Ser. No. 825,220, filed May 16, 1969, entitled Door Assembly and assigned t0 the assignee of this application.

The counterbalancc mechanism 24 (FIG. 3) for the door tt) may be substantially conventional in construction. Specically, the counterbalance mechanism 24 is comprised of a pair of coaxial shafts 26 and 27, in this particular embodiment, which are connected by a flanged coupling 2.8. The shafts are rotatably supported, respectively, by bearings mounted on the brackets 29, 30 and 33, 34, respectively7 which are in turn mounted upon the interior surface of the wall 12. Conical drums 36 and 37 are mounted upon the remote ends of the shafts 26 and 27, respectively, for rotation therewith. A pair of cables 38 and 39 are secured at one end of each to the drums 36 and 37, respectively, near the small ends thereof, and said cables are secured at the other ends thereof to the opposite ends of the lower edge portion of the door I0. The tracks I6, I7, 22 and 23 are supported by means including the brackets 29 and 34, and the hanger structure 42 which may bc supported from a ceiling in a well-known manner.

The shafts 26 and 27 are encircled by a pair of spiral springs 43 and 44, the inner ends of said springs being respectively secured to or anchored upon the brackets 30 and 33, respectively. The remote ends of the springs 43 and 44 are connected to collars 46 and 47, respectively, which are in turn rigidly secured to the shafts 26 and 27, respectively. The springs 43 and 44 are arranged and constructed so that the tension thereon is increased as the cables 38 and 39 are unwound from the drums 36 and 37 in a substantially conventional manner.

A pair of parallel and spaced rails 48 and 49 are rigidly secured at their front ends to the wall 12 by means of a mounting bracket 52. The rear ends of the rails are secured to the cross bar 53, which is part of the hanger structure 42.

The rails 48 and 49 have substantially C-shaped cross sections, as appearing in FIG. 3, for receiving rollers 54 (FIG. 4) mounted on the hangers 56 which are connected to and support the carriage 57. The carriage 57 comprises a mounting frame 58 which is connected to the hangers 56 and which supports an electric motor 59 near the front end thereof. A control box 62 is mounted upon the carriage 57 rearwardly of the motor 59 and connects the motor to a source of electrical potential in any convenient manner, as by means of the conductor 63. The front end of the carriage 57 is connected to the upper end of the door l@ by linkage 64 which is pivotally mounted on the door by the bracket 66 (FIG. l).

A drive sprocket 67 (FIG. 5) is mounted upon and rotatable with the motor shaft 68 and is connected by a chain 69 (FIGS. 4 and 5) to a driven sprocket 72 secured to a shaft 73 which is rotatably mounted upon the carriage 57 by the bearings 74 and 75. An intermediate sprocket 77 is also Secured to and rotatable with the shaft 73 between the bearings 74 and 75 and is engaged with a chain 78, which also engages a sprocket 79 mounted on and rotatable with the shaft 82 which is rotatably supported by the bearings 83 and 84 on the carriage 57. Another sprocket 86 is mounted upon and rotatable with the shaft 82 and engages an endless chain 87 which has an elongated loop extending lengthwise of the rails 4&5 and 49. The rear end of the loop formed by the chain 37 is engaged and supported by a sprocket 88 (FIG. 6) which is rotatably supported upon and between the rearward ends of the rails 48 and 49. The front end of the loop of the chain 87 is engaged with the sprocket 89 which is mounted upon and rotatable with the shaft 27. The motor 59 is of the reversible type so that rotation thereof in a counterclockwise direction (as seen in FIG. causes the carriage 57 to move in a frontward direction, which is leftwardly as appearing in FIGS. 5 and 6. Thus, counterclockwise rotation of the motor shaft 68 effects carriage movement in a rearward direction, whereby the door is opened.

A pair of idler sprockets 92 and 93 (FIG. 5) are secured to and rotatable with shafts 94 and 95, respectively, which shafts are rotatably supported upon the carriage 57 by means of the bearings 97, 9S and 99, 10i), respectively. The idler sprockets 92 and 93 are provided to increase the number of teeth on the sprocket 86 which are in engagement with the chain 37 and, at the same time, prevent the possibility of accidental disengagement of the chain 87 from the sprocket 86.

OPERATION Although the operation of the door assembly and door operator described above will be apparent to persons skilled in the art from the foregoing description, said operation will be summarized hereinafter.

The motor 59 can be energized in any convenient manner as by closing a wall-mounted switch, not shown, connected in series between the control box 62 and a source of electrical potential. If the door 10` is in the closed position, said energization of the motor 59 will rotate the shaft 68 thereof in a clockwise direction as appearing in FIG. 6 whereby the carriage 57 will be moved rearwardly along the rails 48 and 49 due to the engagement between the chain 87 and the sprocket 86. At the beginning of such movement, the lower edge of the door 10 will move upwardly at a slower rate than the rearward movement of the upper edge of the door. Thus, because the motor 59 operates at a constant speed, the carriage 57 will move rearwardly relative to the lower reach of the chain 87 at a faster rate than said lower reach will be moved lengthwise of the rails 48 and 49 away from the wall 12, whereby the rotational speed of the shafts 26 and 27 will be somewhat slower than the average rotational speed during the entire opening movement of the door. The urging of the cables 38 and 39 to raise the lower end of the door 10 will be balanced with the urging of the carriage S7 by this differential adjustment, whereby the resistance to raising movement of the door will be shared more equally by the cables and carriage.

As the door approaches the end of its upward movement, the lower end thereof tends to move faster than the upper end, henced faster than the takeup of the cables. Accordingly, the carriage will move relative to the chain 87 at a slower rate than said chain 87 moves relative to said rails 48 and 49 toward the frontward end of the rails. In other words the urging by the cables and carriage will be automatically adjusted to increase or -decrease their effectiveness in raising the lower and upper edges of the door in response to the demand imposed by the speeds of movement of these parts of the door.

Where the door is made, for example, from two horizontally hinged sections, the vertical and horizontal Gf tracks will normally be connected by curved sections.

It will be seen that appropriate overload switch means, not shown, can be provided with the motor 59 to disconnect the motor from its energy source in case the door strikes an objecdt or is otherwise obstructed by something other than gravity during its movement between the open and closed positions.

Although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A mechanism for moving a closure means between a substantially upright, closed position and a substantially horizontal, open position, the lower portion of said closure means being engaged by flexible element means, comprising:

elongated, substantially horizontal rail means extending from a location near the upper edge of said closure means when it is in said closed position and substantially perpendicular thereto;

carriage means supported by said rail means for movement lengthwise thereof and connected to the upper portion of said closure means;

take-up means including shaft means near said location and connected to said exible element means;

motor means mounted on said carriage means for movement therewith; and

differential drive means connected between said motor means and said shaft means for urging movement of said carriage means and said flexible element means relative to said rail means to effect automatic adjustment of the movements of said flexible element means and said carriage means in response to changes in the relative speeds of movement of the upper and lower portions of said closure means.

2. A mechanism according to claim 1, including springbiased counterbalance means connected to said shaft means and yieldably opposing downward movement of said flexible element means.

3. A mechanism for moving a closure means between a substantially upright, closed position and a substantially horizontal, open position, the lower portion of said closure means being engaged by cable means, comprising:

elongated, substantially horizontal rail means extending from a location near the upper edge of said closure means when it is in said closed position and substantially perpendicular thereto;

carriage means supported by said rail means for movement lengthwise thereof and connected to the upper portion of said closure means;

cable take-up means connected to said cable means and including shaft means near said location;

elongated, exible and endless element means arranged in an elongated loop adjacent said rail means and substantially parallel therewith;V annular means rotatably supporting said loop near the end of said rail means remote from the closed position of said closure means, the other end of said loop` being connected to said shaft means, movement of said element means lengthwise of said rail means effecting vertical movement of said cable means; and

drive means on said carriage means engaged with said element means for urging movement of said carriage means along said rail means, differences in the rates of movements of said upper and lower portions of said closure means relative to said rail means being automatically compensated by changes in the movement of said element means relative to said rail means and said carriage means.

4. A mechanism according to claim 3, wherein said element means includes chain means and wherein said annular means is a sprocket; and

including a second sprocket secured to said shaft means and engaged by said chain means, said drive means including a third sprocket engaged with said chain means between said rst and second sprockets and a motor mounted on said carriage means and driving said third sprocket.

5. A mechanism according to claim 3, wherein said take-up means includes a pair of tapered drums secured to said shaft means, and said cable means comprises a pair of cables, each cable extending between one of said drums and the lower end of the closure means.

6. A mechanism according to claim 4, wherein said drive means causes said third sprocket to rotate at a constant speed, and wherein a change in the rate of movement of the carriage means along the rail means results in an equal and opposite change in the rate of movement of said chain means relative to said rail means, whereby the forces applied by the cable means and the carriage means to the closure means are substantially balanced.

7. A mechanism for moving a one-piece door between a substantially upright, closed position blocking an opening in a wall and a substantially horizontal, open position near the upper end of said opening, comprising:

elongated rail means extending substantially perpendicularly away from said wall means near the upper end of said opening;

substantially horizontal shaft means rotatably snpported upon said wall means near to and transversely of said rail means;

drum means secured to shaft means for rotation therewith;

cable means connected at one end to said drum means and at the other end to said door near the lower end thereof; counterbalance means connected to said shaft means and adapted to resist rotation thereof whereby said cable means is unwound from said drum means;

carriage means supported by and movable along said rail means;

irst sprocket means mounted upon the outer end ot said rail means;

second sprocket means radially aligned with said first sprocket and connected to said shaft means; elongated endless chain means extending around and engaged with said first and second sprocket means7 third sprocket means mounted upon said carriage means and engaged with said chain means between said iirst and second sprocket means; drive means mounted upon said carriage means and connected to said third sprocket means for rotating same at a substantially constant speed; and

linkage means connected between said carriage means and the upper end of said door whereby movement of said carriage means along said rail means moves said door between said closed and open positions, differences in the rates of the movements of the upper and lower ends of said door relative to said rail means being automatically compensated by changes in the movement of said chain means relative to said rail means and said carriage means.

8. A mechanism for moving a closure means between a substantially upright, closed position and a substantially horizontal, open position comprising:

elongated, substantially horizontal rail means extending from a location near the upper edge of said closure means when it is in said closed position and substantially perpendicular thereto;

carriage means supported by said rail means for movement lengthwise thereof and connected to the upper portion of said closure means;

motor means mounted on said carriage means for movement therewith; and

differential drive means connected between said motor means and the lower part of said closure means for effecting automatic adjustment of the movement of said carriage means relative to said rail means in response to changes in the relative speeds of movement of the upper and lower portions of said closure means.

9. A mechanism according to claim 8, wherein said differential drive means includes:

an annular drive member rotatably supported on said carriage means and connected to and rotated by said motor means; and

driven means operatively interconnected to the lower portion of said closure means and disposed in driving engagement with said driving member.

10. A mechanism according to claim 9, wherein said driving member comprises a toothed driving wheel, and wherein said driven means includes an elongated tiexible member.

l1. A mechanism according to claim 8, wherein said differential drive means includes an elongated, flexible, endless means coacting between said carriage means and said closure means.

References Cited UNITED STATES PATENTS 1,792,119 2/1931 Peelle 49-199 2,605,100 7/1952 Matchett 49-200 X FOREIGN PATENTS 767,838 2/1966 Belgium 49-200 J. KARL BELL, Primary Examiner U.S4 Cl. XR. i60-193 

